Dewatering apparatus



J. T. HCYT DEWA'IERING APPARATUS Filed Feb. 1, D24 2 Sheets-Sheet 1 Sept. 25, 1928.

J. T. HOYT DEWATERING APPARATUS Filed Febfl, 1924 2 Sheets-Sheet 2 @ORNEY Patented Sept. 25, 1928.

UNITED STATES PATENT orrice.

JOHN '1'. HOYI, 0F HAZLETON, PENNSYLVANIA, ASSIGNOR T0 UNITED FILTERS GOR PORATION, OF NEW YORK, N. Y.,

A CORPORATION OF DELAWARE.

DEWATERING APPARATUS.

Application filed February 1, 1924. Serial No. 689,939.

This invention relates particularly to the paper making art. and more especially to an apparatus and method for removing the 7 major part of the liquid or effluent water from the pulp so as to concentrate or thicken the fiber content at any particular point in the paper making process, and to other fields wherein the separation of solids from liquids presents a problem.

It is an object of the invention to provide an apparatus arid process for effectively separating the major portion of the liquid from the pulp fibers, which will notbecome clogged or stopped by the resinous or gummy content of the pulp water or liquid.

Another object of the invention is to provide an apparatus of the type described from which the deposited pulp fibers can be cleanly and easily stripped without leaving stray fibers imbedded in the separating medium which would eventually clog the passages through the medium so as to prevent the withdrawal of the liquid therethrough.

Another object of the invention is to provide an apparatus for removing the major part of the liquid from the pulp fibers which is continuous in its operation, wherein'the liquid is removed and the layer of pulp fibers is deposited on the separating medium at one point in the operating cycle, the separating medium is then removed from the pulp liquor, the pulp stripped therefrom, and the separating medium returned to the pulp liquor to deposit another layer of pulp thereon.

Another object of the invention is to provide a novel method of operation and novel construction for a continuous filter which will permit the continuous use of said filter for the filtration of liquids which hitherto could not be commercially filtered in a continuous filter because of the frequent clogging of the filter fabric by constituents of the filtered liquid.

In the apparatus heretofore used for effecting separation of the liquid from the pulp fibers by the use of fabric or wire cloth separating means,-it has been found that the resinous and gummy constituent of the pulp liquors and the pulp fibers themselves, quickly clog the pores of the separating medium where said separating medium is of sufficiently fine texture to remove any considerable percentage of the pulp fiber, and necessitate such frequent and thorough cleaning of the frame as to render their use commercially unprofitable where they could otherwise be dispensed with.

A particularly important feature of my invention is the use of a filter element comprising a drainage member covered with a perforated separating plate of sheet metal or other suitable material, on the surface of which the cake of pulp is deposited, while the pulp eflluent liquor is drawn through the perforations into the drainage member.

As a result of the use of such perforated plate it has been foundthat separators of the type herein described may be used for the withdrawal of liquor from paper pulp and other resinous or gum containing material without having the pores thereof gum or clog up with the resinous material extractedfrom.

the pulp, as has heretofore been the case when the separating medium of fabric or wire mesh cloths have been used. v

Referring now to the drawings which illustrate a preferred form of embodiment of the invention Figure l is a side viewof one form of apparatus for removing water from the pulp; a filter.

Figure 2 is an end View thereof parts beingbroken away to more clearly illustrate structural details.

Figure 3 is a detail view of the pulp removmg means.

Figure 4 is a side elevation of the preferred form of drainage member.

Figure 5 is a side elevation of the assembled separator segment. I

Figure 6 is a sectional view. on the line 66 of Figure 5.

Figure 7 is a sectional view of the 77 of Figure 5.

Figures 8 and 9 are sectional views of a modified form of a separator segment.

Figure 10 is an enlarged detail showing the perforations through the separator plate.

In the preferred embodiment the separator comprises a plurality of rotating leaves or This chamber is substantially in the form of a quarter cylinder open at the top and having a curved side wall. a vertical side wall and substantially quadrant-shaped end walls. The upper surfaces of the chamber walls lie in a plane parallel to a horizontal plane passing through the axis of the shaft and the vertical side wall lies in a plane parallclto a vertical plane passing through the axis of the shaft. The tank further includes a plurality of individual trough-shaped chambers. E crenellated to form individual (fOl1'l]')t1ltlI1OI1l'S spaced from one another in the direction of the length of the tank and communicating with the main chamber E through openings formed in the vertical wall thereof. The individual compartments are positioned to register with the several separator discs A andv the parallel walls thereof are spaced apart sufliciently to permit the discs to rotate free- 1y without danger of striking against the chamber walls.

For a specific description of the discs A, tank D etc, reference may be had to the patent to 0. Salisbury 1,293,555, grantedFebrw ary 4, 1919, and to the application of A. L.

Greater, Sr. 227,519, filed April 9, 1918, now

Patent Number 1,538,980, granted May 26, 1925.

As shown in Figure 2 the rotating discs A are composed of a plurality of sectors A each of which is composed of a wooden or metal drainage member 1 consisting of a rectangular central section I and triangular side sections 1" connected therewith so as to form a sector shape. Ridges 1, run longitudinally of the drainage member to form channels 1 through which the pulp liquor may be drawn toward the inner end of the segments A which communicate by means of the tubular-section 2 with the hollow shaft B, in which a suitable suction exists to draw the liquid through the segments A and discharge same from the shaft B. A separating member 3, comprising a perforated plate of sheet metal or other suitable material covers each side of the segment drainage member 1 and prevents the entrance of the pulp fibers into the channels 1 of the drainage member. I have found it desirable in the practice of the invention to form the holes 3 in the separating plate of a very small diameter in order to prevent passage of the pulp fibers therethrough. A very effective separation can be made with holes approxi mately .020 of an inch in diameter and I provide about 600 of these holes 3 per square inch of the separator in order to permit rapid extraction of the liquid from the pulp. However, it is to be understood that the invention is not limited to this specific size or number of holes, but that the size and number will vary with the nature of the materials being separated.

Near the inner end of the drainage memand clamped therein by the clamping members 4 on the radial rods 5, extending outward from the shaft B, suitable depressions 6 being formed in the rim 1 of the drainage member to receive the rods 5 and clamping members 4.

The shaft B with the separator leaves A thereon is rotated by means of the driving mechanism C to move the leaves slowly through the pulp liquor in the tank D. During .the time the portion of the leaf is im-' mersed in the liquor, the suction in the shaft B, sucks a portion of the liquor through the holes in the separator plates 8 and deposits a cake of the pulp fibers thereon and as the continued rotation of the shaft B moves the leaves with the pulp thereon out of the liquor,

the suction to the portion of the leaf out of the liquor may be cut off or the 'air may be drawn through the pulp cake to remove a further portion of the liquor therefrom, depending upon how dry a pulp is desired.

To remove the pulp cake from the filter leaves prior to their immersion in the pulp liquor again, a pair of rotating rollers or brushes 7 are provided, preferably at the top of the trough-shaped chambers E which contact with each side of each leaf A to strip the cake therefrom. These rollers or brushes 7 are rotated in a-Idirection opposite to the movement of theleaves A and contact wit-h the surface of the separator plates 3 to separate the pulp cake therefrom in substantially sector shaped sheets P which are directed downward between the trough-shaped chambers E as illustrated in Figure 3.

The brushes 7 may be driven by means of a shaft 9, extending longitudinally ofthe tank D and journaled in suitable bearings 10 secured to the floor or base oft-he separator. The rotation of the brushes in a direction opposite to the moven'ient of the leaf not only cleans the surface of the separating medium, but tends to pull out any of the pulp fibers which may have entered into the perforations 3".

A pulley 11 on the shaft 9 is connected by means of a bcltor the like to a suitable source of power by means of which the shaft is rotated. 1

Below each of the brushes 7rand extending parallel therewith is a stud shaft 12 journaled in a bearing 13 on the floor or base of A bevel gear 18 on the end of each shaft 12 meshes with a bevel gear 19 or l9 on the shaft 9 to rotate shaft 12 and consequently the brushes 7 on the opposite side of each filter l of the frame 20 as at 21*.

leaf in opposite direction. It will be understood that by this means the brushes 7 may be rotated a greater or less peripheral speed than the speed of rotation of the leaves A. I have found, however, that better results are secured-by rotating the brushes at a slightly greater speed than the speed of the leaves.

Figures 8 and 9 illustrate'a modified form of sector for the filter leaves A in Which the drainage member comprises a segment shaped skeleton or frame 20, divided by a plurality of longitudinal plates of metal, wood or the like 21 which may be imbedded in the walls Suitable holes 21 permit communication between the source of suction in the shaft B and all portions of the frame 20 to draw the pulp liquor therea from. The open sides of the frame 20 are covered with separator plates 3 suitably perforated to offer low resistance to the flow of the pulp liquor therethrough, but. of small enough size to cause the pulp fibers to mat thereon and prevent the passage of more than a very minute portion of the pulp therethrough.

The smooth surface of the perforated plate and the fact that the perforations are substantially perpendicular to the surface prevent clogging of the filter from the resinous and gummy materials in the liquor, and the smoothness and hardness of the surface permits complete cleaning. Instead of smooth perforated plate it will be obvious that other smooth surfaced permeable substances such as smooth rolled screen, hard porous rubber, stone or the like may be used.

Figure 10 indicates on an enlarged diagrammatic scale the perforations in the plate 3, which are too minute to be shown clearly in Figure 5.

lVhile the invention has been described with particular reference to the filtration or separation of paper pulp from the White I, water or effluent of a paper mill, it will be understood that the use of a perforated plate filtering medium on a continuous filter is not confined to this field but that it may be eflectively used elsewhere when a fine, easy cleaning and non-plugging filter is necessary.

In compliance with the patent statutes '1 have illustrated and described a preferred form of embodiment of my invention, but it is to be understood that various modifications and changes could be made therefrom, with out departing from the spirit of the invention or the scope of the appended claims.

I claim 1. In a dewatering apparatus of the type described, the combination of a tank for containing the solution to be dewatered, a separating, medium, comprising a smooth, fine material on the exposed surface of the plate,

and means to substantially completely clean the separating medium during each cycle of filter operation.

2. In a dewatering apparatus, the combination of a receptacle containing the solution to be dewatcred, a separating medium comprising a smooth perforated plate, means to pass the separating medium through said solution, means to pass the Water through the perforations to effect a separation of the solid and liquid constituents of the solution, and means to remove the solid material from said perforated plate in a substantially continuone sheet.

8. In a continuous high vacuum suction filter for the dewatering of pulp fiber, the combination of a perforated plate filtering medium having smooth sides.

4- In a continuous rotating leaf filter, a filter leaf divided into a plurality of separated sectors, a smooth perforated filtering medium for said sectors, means to rotate said leaves through a solution tank, means to communicate suction to said sectors separately to cause liquid to pass through said sectors to deposit solids on said filtering medium, and a revolving brush pressing against the filtering medium on the sides of said leaves to clean the cake therefrom.

5. In acontinuous rotating leaf filter, a smooth perforated filtering medium for said leaves, means to rotate said leaves through a solution tank, means to cause liquid to pass through said leaves to deposit solids on said filtering medium, a revolving brush pressing against the filtering medium on the sides of said leaves to clean the cake therefrom, means to rotate said brushes in a direction opposite to the movement of said leaves and at a higher peripheral speed than said leaves.

6. Ina dewatering apparatus of the type described, areceptacle containing the solution to be separated, a rotating shaft extending described, a receptacle containing the solution to be separated, a rotating shaft extending across the receptacle, a plurality of filter leaves consisting of a perforated metal sheet, means to rotate the leaves through said solution to deposit a layer of the solid material on said separating medium, and means rotating in the opposite direction to said leaves to remove the solid material from the separating medium.

8. In an apparatus of the typedescribed, the combination of-a tank containing the solution to be separated, a plurality of separating leaves, means to rotate the leaves through the solution, means to cause separation of the liquid and solid material of said solution to deposit'a layer of the solid material on each side of the leaves, a brush on each side of each leaf and means to rotate the brushes in a direction opposite to the rotation of the leaves to separate the layer of solid material from the leaves.

9. In an apparatus of the type described, a sector-shaped drainage member, means to communicate suction or pressure from one end of the drainage member to all portions thereof, and a perforated sheet metal plate covering the sides of the drainage member.

10. In an apparatus of the type described, a sector-shaped drainage member, comprising a rectangular central section, a substantially triangular section at each side of said rectangular section and said triangular section having a pluralit of ridges extending longitudinally of said member and communieating with a passageway through the small end of said drainage mem r.

11. In an apparatus of the class described, a drainage member, comprising a sectorshaped frame, means to communicate suction to all portions of said frame, and a perforated late covering the sides of said frame.

12. n an apparatus of the type described, a crenellated tank containin the solution to be separated, a plurality of leaves, one in each crenellation of said tank, means to rotate the leaves through said solution, means to effect separation of the liquid and solid material of said solution at the sides of said leaves comprising a smooth surfaced filtering medium, to deposit a layer of the solid ma terial thereon, a brush contacting with the side of each leaf and means to rotate said brushes in a direction opposite to the rotation of said leaves to separate the solid layer from the leaves and clean the sides thereof.

13. The combination in a continuous suction filter of a perforated plate filtering medium of sufficiently fine mesh to form a filtering layer from the solids in the sludge to be filtered and sufliciently open to prevent clogging thereby and having about 600 perforations of .020" diameter per square inch of exposed surface.

14. In an apparatus of the type described, a sector-shaped drainage member, means to communicate suction or pressure from one end of the drainage member to all portions thereof, a perforated sheet metal plate covering the side of the drainage member, said plate having approximately 625 perforations of .02 diameter per square inch of surface.

- 15. The method of reducing the pul content in the white water of a paper mi 1 containing resinous and gummy materials Which rapidly clog the pores of a woven filter fabric, by the use of a continuous filter, which comprises passing the white water through a hard smooth surfaced filter medium having perforations at right angles therethrough, permittin the pulp to form an initial filter layer on sai smooth surfaced filter medium to assist in the further separation of the pulp from the Water, and completely removing the collected pulp from the surface of the filter medium once in each cycle of operation of the filter.

16. The method of separating, by the use of a continuous filter, the liquid and solid portions of a. sludge containing constituents which rapidly clog the pores of a woven filter medium, which comprises passing the liquid of said sludge through a hard smooth surfaced filter medium 7 therethrough sufliciently small to arrest the passage of a part of the solids but insuflicient to arrest the passage of all the solids or to be clogged thereby, to form an initial filtering layer of the solids in said sludge during which initial period a cloudy filtrate is discharged, continuing the filtration to deposit additional solids on the initial filtering layer during which period a clear filtrate is discharged, and completely removing the collected solids from the filtering surface and repeating sai series of steps during each cycle of filter operation.

17. The method of using a continuous filter for the filtration of sludges containing constituents which normally clog a fine mesh woven filter medium, which comprises passing the liquid of said sludge through a perforated plate filtering medium having perforations not sufficiently small to prevent the passage of all solids clogged thereby, but sufficient to form an initial filter bed from the solids in said sludge on the filter medium, continuing the deposition of solids on said initial filter bed, completely removing the solids during each cycle of filter operation and repeating said step during the'next filter cycle.

18. The method of using a continuous filterfor the separation of paper pulp from water, the resinous and gummy constituent of which quickly clogs a woven filter medium which comprises covering the filter with a perforated metal plate filtering medium, moving said medium through a pulp solution, forcing the water rapidly through posit an initial layer of pulp thereon, continu ing the passage of water through said filtering medium and said initial pulp layer to increase the deposition of pulp, and substantially completely cleaning said filtering medium during each cycle of filter operation.

19. The method of using a high vacuum from said filter mediumhaving perforations therethrough or to become said medium to de- I rotary continuous filter for the continuous continuing the filtration period to de osit adfiltration of sludges containing materials ditional solids on the initial filter d, diswhich rapidly clog a woven filter medium, charging a clear filtrate during said continuwhich comprises providing a filter medium of' ing periodv and completely removin the de- 5 smooth, perforated metal plate, passing said posited solids from said plate during each 15 sludge liquor through said plate at the start a cycle of filter operation. of the filtration period to form an initial In testimony whereof I have afiixed my filter bed of the solids in said sludge on said signature to this specification. perforated plate, discharging a cloudy filtrate 10 during the formation of the initialfilter bed, JOHN T. HOYT. 

